Comparing diagnostic techniques of magnetic resonance angiography (MRA) and Doppler ultrasonography in determining severity of renal artery stenosis

BACKGROUND: Renal artery stenosis is one of the important causes of hypertension and endstage renal failure. Magnetic resonance angiography (MRA) and Doppler ultrasonography arenon-invasive and safe diagnostic techniques that have also high sensitivity and specificity. Sincethe accuracy and reliability of these techniques depend upon technicians and softwares, wedecided to evaluate and compare the sensitivity and specificity of these techniques in Isfahan.METHODS: Our study included all the patients (37 patients) who underwent renal arteryangiography during 2 years from May 2003 to May 2005 and up to six months after that hadunderwent MRA (21 patients) and Doppler sonography (16 patients) in Isfahan. Renal arteryangiography was considered as the gold standard.RESULTS: Sensitivity, specificity, positive and negative predictive values of 100%, 25%, 25%,and 100% were obtained for MRA respectively. Specificity and positive predictive values (PPV)of Doppler sonography were 67%. Its sensitivity and negative predictive values (NPV) were 57%.CONCLUSION: Although it seems that technician dependency, technical and softwareproblems were the reasons of low specificity of gadolinium-enhanced MRA in our study, furtherstudies with larger sample sizes are recommended.Keywords: MRA, Doppler Ultrasonography, Renal Artery Stenosis

Evaluation of accuracy of Euroscore risk model in prediction of perioperative mortality after coronary bypass graft surgery in Isfahan*

Background: This study aimed to evaluate the accuracy of Euroscore (European System for Cardiac Operative Risk Evaluation) in predicting perioperative mortality after cardiac surgery in Iranian patient population. Methods: Data on 1362 patients undergoing coronary bypass graft surgery (CABG) from 2007 to 2009 were collected. Calibration was assessed by Hosmer-Lemeshow goodness-of-fit. Area under the curve (AUC) was used to assess score validity. Odds ratios were measured to evaluate the predictive value of each risk factor on mortality rate. Results: The overall perioperative in hospital mortality was 3.6% whereas the Euroscore predicted a mortality of 3.96%. Euroscore model fitted well in the validation databases. The mean AUC was 66%. Mean length of intensive care unit (ICU) stay was 2.5 ± 2.5 days. Among risk factors, only left ventricular dysfunction, age and neurologic dysfunction were found to be related to mortality rate. Conclusions: Euroscore did not have acceptable discriminatory ability in perioperative in hospital mortality in Iranian patients. It seems that development of a local mortality risk scores corresponding to our patients epidemiologic characteristics may improve prediction of outcome